'\" te
.\"  Copyright 1989 AT&T  Copyright (c) 2000, Sun Microsystems, Inc.  All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
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.TH DDI_COPYOUT 9F "Apr 19, 2000"
.SH NAME
ddi_copyout \- copy data from a driver
.SH SYNOPSIS
.nf
#include <sys/types.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>



\fBint\fR \fBddi_copyout\fR(\fBconst void *\fR\fIdriverbuf\fR, \fBvoid *\fR\fIbuf\fR, \fBsize_t\fR \fIcn\fR, \fBint\fR \fIflags\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI).
.SH PARAMETERS
.ne 2
.na
\fB\fIdriverbuf\fR\fR
.ad
.RS 13n
Source address in the driver from which the data is transferred.
.RE

.sp
.ne 2
.na
\fB\fIbuf\fR\fR
.ad
.RS 13n
Destination address to which the data is transferred.
.RE

.sp
.ne 2
.na
\fB\fIcn\fR\fR
.ad
.RS 13n
Number of bytes to copy.
.RE

.sp
.ne 2
.na
\fB\fIflags\fR\fR
.ad
.RS 13n
Set of flag bits that provide address space information about \fIbuf\fR.
.RE

.SH DESCRIPTION
This routine is designed for use in driver \fBioctl\fR(9E) routines for drivers
that support layered ioctls. \fBddi_copyout()\fR copies data from a driver
buffer to a destination address, \fIbuf\fR.
.sp
.LP
The \fIflags\fR argument determines the address space information about
\fIbuf\fR. If the \fBFKIOCTL\fR flag is set, this indicates that \fIbuf\fR is a
kernel address, and  \fBddi_copyout()\fR behaves like \fBbcopy\fR(9F).
Otherwise,  \fIbuf\fR is interpreted as a user buffer address, and
\fBddi_copyout()\fR behaves like \fBcopyout\fR(9F).
.sp
.LP
Addresses that are word-aligned are moved most efficiently.  However, the
driver developer is not obliged to ensure alignment.  This function
automatically finds the most efficient move algorithm according to address
alignment.
.SH RETURN VALUES
Under normal conditions, \fB0\fR is returned to indicate a successful copy.
Otherwise, \(mi\fB1\fR is returned if one of the following occurs:
.RS +4
.TP
.ie t \(bu
.el o
Paging fault; the driver tried to access a page of memory for which it did not
have read or write access.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Invalid user address, such as a user area or stack area.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Invalid address that would have resulted in data being copied into the user
block.
.RE
.RS +4
.TP
.ie t \(bu
.el o
Hardware fault; a hardware error prevented access to the specified user memory.
For example, an uncorrectable parity or \fBECC\fR error occurred.
.RE
.sp
.LP
If \(mi\fB1\fR is returned to the caller, driver entry point routines should
return \fBEFAULT\fR.
.SH CONTEXT
\fBddi_copyout()\fR can be called from user or kernel context only.
.SH EXAMPLES
\fBExample 1 \fR\fBddi_copyout()\fR example
.sp
.LP
A driver \fBioctl\fR(9E) routine (line 12) can be used to get or set device
attributes or registers. In the \fBXX_GETREGS\fR condition (line 25), the
driver copies the current device register values to another data area.  If the
specified argument contains an invalid address, an error code is returned.

.sp
.in +2
.nf
1  struct device  {        /* layout of physical device registers  */
 2     int      control;    /* physical device control word  */
 3     int      status;     /* physical device status word   */
 4     short    recv_char;  /* receive character from device */
 5     short    xmit_char;  /* transmit character to device  */
 6  };

 7  struct device_state {
 8     volatile struct device *regsp;   /* pointer to device registers */
 9     kmutex_t reg_mutex;              /* protect device registers */
       ...
10  };

11  static void *statep; /* for soft state routines */

12  xxioctl(dev_t dev, int cmd, int arg, int mode,
13      cred_t *cred_p, int *rval_p)
14  {
15      struct device_state *sp;
16      volatile struct device *rp;
17      struct device reg_buf;     /* temporary buffer for registers */
18      int instance;

19      instance = getminor(dev);
20      sp = ddi_get_soft_state(statep, instance);
21      if (sp == NULL)
22          return (ENXIO);
23      rp = sp->regsp;
        ...
24      switch (cmd)  {

25      case XX_GETREGS:   /* copy registers to arg */
26            mutex_enter(&sp->reg_mutex);
27            /*
28             * Copy data from device registers to
29             * temporary device register buffer
30             * e.g. reg_buf.control = rp->control;
31             */
32            mutex_exit(&sp->reg_mutex);
33            if (ddi_copyout(&reg_buf, arg,
34                sizeof (struct device), mode) != 0) {
35                    return (EFAULT);
36            }

37            break;
38      }
39  }
.fi
.in -2

.SH SEE ALSO
.BR ioctl (9E),
.BR bcopy (9F),
.BR copyin (9F),
.BR copyout (9F),
.BR ddi_copyin (9F),
.BR uiomove (9F)
.sp
.LP
\fIWriting Device Drivers\fR
.SH NOTES
The value of the \fIflags\fR argument to \fBddi_copyout()\fR should be passed
through directly from the \fImode\fR argument of \fBioctl()\fR untranslated.
.sp
.LP
Driver defined locks should not be held across calls to this function.
.sp
.LP
\fBddi_copyout()\fR should not be used from a streams driver. See
\fBM_COPYIN\fR and \fBM_COPYOUT\fR in \fISTREAMS Programming Guide\fR.
